docs: def _get_expiration(self, headers: dict) -> int:
          """Gets the expiration time of the data from the response headers.
  
          Args:
              headers: dictionary of headers from ESI
  
          Returns:
              value of seconds from now the data expires
          """
          expiration_str = headers.get('expires')
          if not expiration_str:
              return 0
          expiration = datetime.strptime(expiration_str, '%a, %d %b %Y %H:%M:%S %Z')
          delta = (expiration - datetime.utcnow()).total_seconds()
          return math.ceil(abs(delta))